Field
This disclosure relates generally to semiconductor integrated circuits having a memory, and more specifically, to having a memory with redundancy.
Related Art
Redundancy in memories has been found to be advantageous because typically the vast majority of the bits meet a specified criteria and only a relatively few do not. Though many failed bits are single bit failures, they often nonetheless come in locations that are in close proximity such as along a row or column. Thus, it has been found to be efficient to replace whole sets of rows or sets of columns with redundant elements of corresponding size in order to replace all types of bit failures. This is considered easier to implement than other approaches. Thus, typical schemes are much less effective when there are single bit failures scattered among the rows and columns since large redundant elements are used to replace a single bit failures.
Accordingly there is a need to provide further improvement in redundancy, especially for single bit failures.